You’ve probably thought of ways that a company could improve a product or service, treat its workers or its customers better or maybe you’ve got an idea of how a company could more efficiently use its resources. But you likely felt powerless to really do anything about it.

As an investor, though, you have the power to help companies do better. The Securities Exchange Act of 1934 gives you the right to file shareholder resolutions and vote on these proposals at company meetings, and this gives you a say in how a company operates.

Investors have used these rights to help hundreds of companies make significant improvements, like cleaning up products for children by getting toxins out, saving money on electricity, or disclosing how much money companies spend on lobbying and political contributions. Shareholders have filed more than 700 proposals in the last two years alone, according to the U.S. Forum for Sustainable and Responsible Investment (USSIF).

Just last month, ExxonMobil shareholders voted to require the oil company to report on how climate change regulations will affect its bottom line, something most other major oil companies, like BP and ConocoPhillips, are already doing.

Even if a particular proposal doesn’t pass, it still can make a difference by bringing an important issue to the attention of company management. “The process of filing often prompts productive discussion, leading to agreements between the filers and management that enable the filers to withdraw their resolutions,” USSIF noted in its biennial 2016 report on trends in sustainable investing.